镧、铕对白沙枇杷试管苗生根效应的研究

将不同浓度的La(NO3 ) 3 ,Eu(NO3 ) 3 加入白沙枇杷组培苗生根培养基中 ,2 0d后分别调查各处理的生根率、生根数 ,并记录根系生长动态 ;44d后切下各处理的根称重并测定其过氧化物酶及硝酸还原酶的活性。结果表明 ,白沙枇杷生根培养基 1/2MS +IBA 0 5 μmol·L- 1 中加入 1 0～ 3 0 μmol·L- 1 La (NO3 ) 3 ,2 0～ 3 0 μmol·L- 1 Eu(NO3 ) 3 均可显著提高其生根率、促进根的伸长生长和根重量的增加 ,增强根系过氧化物酶及硝酸还原酶的活性。但La(NO3 ) 3 和Eu(NO3 ) 3 对白沙枇杷组培苗生根效应有些差异 ,La(NO3 ) 3 对生根数、根长的增加作用及对过氧化物酶的激活作用比Eu(NO3 ) 3 显著 ,而Eu(NO3 ) 3 对根鲜重的增加、硝酸还原酶的激活作用比La(NO3 ) 3 明显得多     

La(NO3)3对蛹虫草活性物质含量的影响EI北大核心CSCD

蛹虫草是一种著名的药用和食用真菌,研究者们常在培养基中添加亚硒酸钠、Fe SO4等无机物来提高蛹虫草活性物质的含量。本文采用高效液相色谱法和紫外分光光度法测定了La(NO3)3处理后蛹虫草活性物质的含量,探究La(NO3)3对蛹虫草活性物质含量的影响。结果表明,在实验浓度范围内,10,50和200 mg·L-1这3个浓度对蛹虫草的活性物质含量影响较大。La(NO3)3浓度为10 mg·L-1时,对喷司他丁、虫草酸和多糖合成具有促进作用,其含量分别为空白组的6.2倍、2.4倍和1.3倍,La(NO3)3对蛹虫草的腺苷和N6-2-羟乙基腺苷合成具有抑制作用,其含量仅为空白组的24.29%和16.87%。La(NO3)3浓度为50 mg·L-1时,对虫草素合成具有显著促进作用,其含量为空白组的8.2倍,La(NO3)3对多糖合成具有抑制作用,其含量仅为空白组的73.14%。La(NO3)3浓度为200 mg·L-1时,对腺苷和N6-2-羟乙基腺苷合成具有促进作用,其含量分别为空白组的1.5倍和2.6倍。La(NO3)3对麦角甾醇和蛋白质的含量未产生显著影响(P>0.05)。     

硝酸镧对大鼠肝脏的亚慢性毒性实验研究

以大鼠为对象,连续用生理盐水和20,10,2,0．2,0．1mg.kg^-1La(NO3)3灌胃6个月后,观察了体重,肝体比变化;检测了血清中谷草转氨酶,谷丙转氨酶,碱性磷酸酶和δ－谷氨酰转移酶含量的变化,应用组织化学及透射电镜技术观察了不同剂量La(NO3)3对大鼠肝脏形态结构的影响。20mg/kg^-1La(NO3)3组动物体重增长缓慢,0．1mg.kg^-1La(NO3)3组动物体重增加较快;20mg/kg^-1La(NO3)3组肝脏汇管区有炎细胞浸润,有些肝细胞内有少量的脂滴,糖原减少,线粒体基质密度增高,有电子密度高的致密体,肝细胞核形态正常或轻度变形。     

魔角旋转核磁共振代谢组学方法对镧、铈急性生物效应的比较研究

利用高分辨魔角旋转核磁共振(MAS 1H NMR)技术对腹腔注射不同剂量[2, 10, 50 mg/kg(体重)]的硝酸镧[La(NO3)3]和硝酸铈[Ce(NO3)3] 的雄性Wistar大鼠肝、肾组织的MAS 1H NMR谱进行比较分析, 研究了La(NO3)3和Ce(NO3)3的急性生物效应, 并结合模式识别技术对不同剂量La(NO3)3和Ce(NO3)3的急性生物效应进行了分类. 研究结果表明, La(NO3)3对大鼠的急性毒性主要表现为肝毒, Ce(NO3)3对大鼠肝、肾同时造成损伤. 该方法可用于其它稀土及金属化合物的毒性预测和毒理学研究.     

镧、铈对酸雨胁迫下龙眼(Dimocarpus longana Lour.)花粉萌发和坐果的影响

研究了La3+和Ce3+对酸雨胁迫下龙眼花粉萌发和坐果的影响.结果表明,酸雨胁迫下,低浓度(0.1～1 μmol·L-1)的La(NO3)3或Ce(NO3)3可以减轻酸雨对花粉的伤害,提高花粉萌发率,高浓度(10 μmol·L-1)则加重了酸雨的伤害作用;0.1～10 mmol·L-1的La(NO3)3和Ce(NO3)3均可以提高龙眼的坐果率,减轻酸雨对龙眼果实的伤害.     

重金属铅胁迫下镧对螺旋藻生长及生理特性的影响

以鄂尔多斯高原碱湖钝顶螺旋藻为实验材料,在Pb(NO3)2(70 mg·L-1)胁迫下,采用生理学方法研究了不同浓度La(NO3)3对螺旋藻生长速率、叶绿素a含量、硝酸还原酶及谷氨酸脱氢酶活性的影响。结果表明:各处理组在培养初期生长速率差异不大(P0.05),6 d后添加La(NO3)3的各处理组螺旋藻的生长速率显著高于对照(P0.05);当La(NO3)3处理浓度为8μg·L-1时可显著促进螺旋藻叶绿素a的合成,有效缓解Pb(NO3)2对硝酸还原酶及谷氨酸脱氢酶活性的影响(P0.05),高浓度La(NO3)3则会与Pb(NO3)2协同、抑制螺旋藻的生长。     

长期口服硝酸稀土对大鼠腺垂体生长激素细胞的影响

为查明La(NO3)3和农用混合稀土"常乐"长期服用后对大鼠腺垂体中生长激素细胞功能和结构的影响,Wistar大鼠口服不同剂量La(NO3)3和"常乐"后,检测血清中生长激素水平的变化,观察腺垂体中生长激素细胞的超微结构。发现口服6个月后,20mg·kg-1组生长激素水平明显低于对照组,0.2及0.1mg·kg-1组则明显增高;停服1个月后,0.2,0.1mg·kg-1组血清中生长激素水平显著高于对照组。口服6个月后,20mg·kg-1组生长激素细胞内分泌颗粒明显减少,线粒体肿胀,粗面内质网腔明显扩张,细胞核变形;停服1个月后,20mg·kg-1组各种改变有所恢复,0.1mg·kg-1组生长激素细胞分泌颗粒较密集。     

硝酸镧对大鼠肝脏癌前病变发展的抑制作用及机制的初步探讨

研究硝酸镧对大鼠肝脏癌前病变的抑制作用及机制. 采用肝癌发生的短期动物模型, 连续用0.2, 10 mg·kg-1的La(NO3)3灌胃2个月后, 观察了不同剂量La(NO3)3对大鼠肝脏形态结构的影响, 免疫组化技术检测肝脏中细胞周期素D1和P16及PCNA的表达, 并做半定量分析. 同时取脾细胞进行淋巴细胞转化率试验. 结果表明, 0.2 mg·kg-1剂量硝酸镧组动物健康状况明显改善, 肝癌前病变程度明显减轻, cyclinD1, PCNA表达下降, P16表达上升, 淋巴细胞转化率升高. 提示低剂量硝酸镧具有一定阻抑肝癌前病变的作用.     

镧离子及其配合物对植物花粉细胞质膜透性及花粉萌发的影响

以植物花粉细胞为试验体系 ,研究La3 及其配合物对花粉质膜透性及花粉萌发的影响。La3 浓度为 1× 10 - 7～ 1× 10 - 4 mol·L- 1 ,可显著减小细胞的质膜透性 ;稀土稳定配合物La3 EDTA对细胞质膜透性基本无影响 ,而La3 柠檬酸、La3 酒石酸的配合物对质膜透性的影响与其配比有关 ,当配比不大于 1∶3时 ,明显降低质膜透性 ,达到 1∶10时 ,无任何作用。La3 浓度在合适的范围内 ( 2 5～ 2 0 μmol·L- 1 )对花粉萌发有明显的促进作用。因此 ,La3 及其某些配合物浓度在 1× 10 - 6 ～ 1× 10 - 5 mol·L- 1 范围内不仅可以减小花粉细胞的质膜透性 ,而且还能促进花粉萌发。     

硝酸镧影响黑曲霉黄酮类化合物生成机制的初步探讨

工业利用微生物生产黄酮类化合物提供研究基础,在培养基中添加不同浓度La(NO3)3,研究黑曲霉合成黄酮类化合物的机制.采用超声波法提取黑曲霉胞内黄酮类化合物,分光光度法表征黄酮总量(芦丁计),HPLC法分析La(NO3)3对黑曲霉黄酮类化合物合成的影响,酶联免疫试剂盒测定黄酮类化合物合成相关酶活性.结果显示:La(NO...     

Synthesis of γγγ-trifluorocarbonyl compounds

γγγ-Trifluorocarbonyl compounds are easily obtained in a good yield by introduction of the 1,1,1-trifluoroethyl moiety (CF₃-CH₂-) on the -methylene group of a ketone.     

Die Kristallstruktur des W3CoB3 und der dazu isotypen Phasen Mo3CoB3, Mo3NiB3 und W3NiB3

Zusammenfassung Mo₃CoB₃, Mo₃NiB₃, W₃CoB₃ und W₃NiB₃ kristallisieren in einem eigenen Typ (W₃CoB₃-Struktur). Das trigonal prismatische Bauelement [T ₆B]^* ist zu Ketten vereinigt, wobei B₃-Gruppen entstehen. Die Phasen sind vermutlich Bor-reicher als obiger Formel entspricht.

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The crystal structure of W₃CoB₃ and the isotypic phases Mo₃CoB₃, Mo₃NiB₃, and W₃NiB₃

Mo₃CoB₃, Mo₃NiB₃, W₃CoB₃, and W₃NiB₃ were found to possess a new type of crystal structure (W₃CoB₃-structure type). Trigonal prismatic groups [T ₆B]^* are linked together forming chains in such a way that B₃-groups occur. These borides do probably exist with a larger amount of boron as to compared with the formula.

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K3SbSe3, Rb3SbSe3 und Cs3SbSe3 – Synthese und Kristallstruktur

K₃SbSe₃, Rb₃SbSe₃, and Cs₃SbSe₃ – Synthesis and Crystal Structure The compounds K₃SbSe₃, Rb₃SbSe₃ and Cs₃SbSe₃ were synthesized by heating mixtures of Sb₂O₃ and an alkalicarbonate in a stream of hydrogen saturated by selenium in a temperature range between 750 °C and 800 °C. The compounds crystallize isostructural with Na₃AsS₃. A comparison of atomic distances and bond angles with those of the isostructural arsenic and bismuth compounds shows the effect of lone pairs.     

γ-Nitro-γ-butyrolacton

γ-Nitro-γ-butyrolactone By oxidation of 3-(1-nitro-2-oxocyclohexyl)propanal ( 1 ) with KMnO₄, besides 3-(1′-nitro-2′-oxocyclohexyl)pripionic acid ( 2 ), the complete hydrolysis product 4-oxononanedioic acid ( 4 ) and the oxidized semi-hydrolysis product 5-(2-nitro-5-oxotetrahydro-2-furyl)pentanoic acid ( 3 ) were formed. The crystalline 3 decomposes at r.t. forming 4 and nitrous gases; its structure was established by X-ray determination.     

Freezing the polarization of CH3NH3PbI3 and CH3NH3PbI3-xClx perovskite films

Thin films of methylammonium lead halides, CH₃NH₃PbI₃ and CH₃NH₃PbI_3-xCl_x, were deposited onto symmetrical microstructured electrode arrays of gold or platinum on Si/SiO₂ wafers. Polarization studies were carried out on perovskite films under vacuum in the dark. For poling, a constant voltage was applied to the samples while the temperature was cycled between 295 K and 4 K. The measured current densities depending on the temperature showed distinct characteristics relating strongly to the crystal phase and the dielectric properties of the perovskite films. Voltage sweeps were carried out at different scan rates at specific temperature intervals after poling. The polarization of the films due to the migration of iodide vacancies in direction of the blocking perovskite/metal interface was frozen almost up to room temperature. Charge carriers were only able to cross the blocking barrier and contribute to the current where the ions have accumulated during poling. All J-V curves showed hysteresis: inverted and regular hysteresis at room temperature and below, respectively. Inverted hysteresis originates from the slow accumulation of ions at the blocking barrier, while regular hysteresis arises from a distortion in the adjacent crystals which will be discussed.     

K3BiSe3, Rb3BiSe3 und Cs3BiSe3 – Substitutionsvarianten des Th3P4-Typs

K₃BiSe₃, Rb₃BiSe₃, and Cs₃BiSe₃ – Derivatives of the Th₃P₄ Structure Type The compounds K₃BiSe₃, Rb₃BiSe₃, and Cs₃BiSe₃ were synthesized by heating mixtures of Bi₂O₃ and the respective alkalicarbonate in a stream of hydrogen saturated by selenium at 850°C. Thin crystals of the compounds appear red in transmitted light. They crystallize isostructural with Na₃AsS₃, space group P2₁3, lattice constants a = 9.771(5) Å, a = 10.161(3) Å, and a = 10.587(5) Å for K₃BiSe₃, Rb₃BiSe₃, and Cs₃BiSe₃, respectively. The Na₃AsS₃ structure type is a derivative of the Th₃P₄ structure type.     

Synthesis of some derivatives of 3-amino-3-desoxyerythrose and 3-amino-3-desoxy-D-3-erythrose

The synthesis of derivatives of 3-amino-3-deoxy-L-erythrose by LAH or LAD reduction of the oxime of 1,2-O-isopropylidene α-L -glycero-tetros-3-ulofuranose is described.     

Die Akzeptoreigenschaften von AsCl3, AsBr3, asJ3, SbCl3, SbBr3 und SbJ3

Zusammenfassung Es wurden die Enthalpien der Reaktionen von AsCl₃, AsBr₃, AsJ₃, SbCl₃, SbBr₃ und SbJ₃ mit Tributylphosphat, N,N-Dimethylacetamid und Hexamethylphosphorsäuretriamid bestimmt. Das Verhalten der Addukte bei Gegenwart eines Überschusses der Donoren wird beschrieben.

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Acceptor properties of AsCl₃, AsBr₃, AsI₃, SbCl₃, SbBr₃, and SbI₃

The enthalpies of the reactions of AsCl₃, AsBr₃, AsI₃, SbCl₃, SbBr₃ and SbI₃ with tributylphosphate, N,N-dimethylacetamide and hexamethylphosphoric acid triamide were measured. The behavior of the adducts in the presence of excess donor molecules is described.

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3x-pyrrolizin-3-ones

Condensation of pyrrole-2-dithiocarboxylates with CH acids containing ester groups, in the KOH-DMSO system, was used to prepare previously unknown 1-alkylthio-3H pyrrolizin-3-ones. The latter, treated with secondary amines, are readily converted to the corresponding 1-amino derivatives.     

3-H-pyrrolizin-3-ones

Previously unknown 1-alkylthio-3H-pyrrolizin-3-ones have been obtained by the condensation of pyrrole-2-dithiocarboxylates with CH acids containing ester groupings in the KOH-DMSO system. On treating the products with secondary amines they are readily converted into the corresponding 1-amino derivatives.Irkutsk Branch of the Russian Academy of Sciences, Irkutsk 664033. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 919–924, July, 1996. Original article submitted May 2, 1996.